McDonald's said Monday it wants its suppliers of pork to do away with controversial gestation stalls used to confine sows.

Gestation stalls are narrow two-feet-wide cages used to confine breeding sows, which bear offspring that are slaughtered to make breakfast sausage and other pork products. By giving each animal its own pre-birthing space, including its own eating space, pork producers cut down on the potential for fights and injuries to both the animals and their handlers. But the Humane Society and McDonald's object to a situation in which females of breeding age spend much of their lives in spaces so small they can't turn around or mingle with other pigs.

“McDonald's believes gestation stalls are not a sustainable production system for the future, the company said in a statement. There are alternatives that we believe are better for pregnant sows, it added. The company said it was acting with the support of the Humane Society of the United States.

McDonald’s is calling on its suppliers to phase out the stalls or crates by May. The HSUS has been a long-time advocate for ending the use of gestation crates, and McDonald's announcement is important and promising, Human Society President Wayne Pacelle said in a statement. We are pleased to see a number of our U.S. suppliers adopting commercially viable alternatives, he added.

This step from McDonald’s comes just two months after Smithfield Foods, the largest pork producer in the world, recommitted to its pledge that it would phase out crates in its company-owned operations by 2017, and about a week after Hormel announced that it would do the same. There are currently about 5.8 million breeding sows in pork production operation in the U.S., according to the U.S. Department of Agriculture data.